Method of forming micro pattern in semiconductor device

ABSTRACT

A method of forming a fine pattern in a semiconductor device includes forming an target layer, a hard mask layer and first sacrificial patterns on a semiconductor substrate; forming an insulating layer and a second sacrificial layer on the hard mask layer and the first sacrificial patterns; performing the first etch process so as to allow the second sacrificial layer remain on the insulating layer between the first sacrificial patterns for forming second sacrificial patterns; removing the insulating layer placed on the first sacrificial patterns and between the first and second sacrificial patterns; etch the hard mask layer through the second etch process utilizing the first and second sacrificial patterns as the etch mask to form a mask pattern; and etch the target layer through the third etch process utilizing the hard mask pattern as the etch mask.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority from Korean Patent Application No.2007-28783, filed on Mar. 23, 2007, the contents of which areincorporated herein by reference in its entirety.

BACKGROUND OF THE INVENTION

The present invention relates to a semiconductor device, and moreparticularly to a method of forming a micro pattern in a semiconductordevice which is finer than the resolution of the exposure equipment.

As a semiconductor device becomes more integrated, a required minimumline width becomes reduced. However, the development of the exposureequipment for realizing a required fine line width of such ahigh-integrated device is not satisfied. In particular, in a case wherethe fine line width which of less than 50 nm needs to be obtained byconventional exposure equipment, the resolution ability of theconventional exposure equipment is limited.

SUMMARY OF THE INVENTION

The present invention relates to a method of forming a micro pattern ina semiconductor device which is finer than a resolution of the exposureequipment.

The method of forming a micro pattern in a semiconductor deviceaccording to the first embodiment of the present invention comprises thesteps of forming an target layer, a hard mask layer and firstsacrificial patterns on a semiconductor substrate; forming an insulatinglayer and a second sacrificial layer on the hard mask layer and thefirst sacrificial patterns; performing the first etch process so as toallow the second sacrificial layer remain on the insulating layerbetween the first sacrificial patterns for forming second sacrificialpatterns; removing the insulating layer placed on the first sacrificialpatterns and between the first and second sacrificial patterns; etchingthe hard mask layer through the second etch process utilizing the firstand second sacrificial patterns as the etch mask to form a mask pattern;and etching the target layer through the third etch process utilizingthe hard mask pattern as the etch mask.

In the above method, the target layer is formed of an insulating layer,a conductive layer or an inter-insulating layer. The hard mask layer hasa stack structure consisting of an amorphous carbon layer and a siliconoxynitride (SiON) layer.

The first sacrificial layer is formed of a polysilicon layer, a siliconoxide (SiO₂,) layer, a tungsten layer or a SOG (spin on glass) layer.The first sacrificial pattern has a critical dimension that isapproximately half of a pitch between the micro patterns formed throughthe final process. The insulating layer is formed from amorphous carbonlayer, silicon oxide (SiO₂), a tungsten (W) or a SOG (spin on glass).

The insulating layer is formed from material having an etch selectivitywith respect to material utilized for forming the second sacrificiallayer and the first sacrificial pattern. The insulating layer depositedon a side surface of the first sacrificial pattern has a thickness thatis approximately half of a pitch between the micro patterns formedthrough the final process.

The second sacrificial layer is formed from conductive material orinsulative material. The second sacrificial layer is formed of a SOG(spin on glass) layer, an organic bottom anti-reflective coatingcontaining silicon such as a multi-functional hard mask layer, a siliconoxide (SiO₂) layer, a tungsten (W) layer or a polysilicon layer. If SOGis used for forming the second sacrificial layer, a heat treatmentprocess is further performed after a deposition process.

The second sacrificial layer is etched through the etchback process. Thesecond sacrificial pattern is remained such that the second sacrificialpattern is leveled with the first sacrificial pattern when the secondetch process is performed. The insulating layer is removed through a dryetch process utilizing oxygen (O₂) plasma. The insulating layer has anetch selectivity with respect to material utilized for forming the firstsacrificial pattern and the second sacrificial layer when the first etchprocess and the process for removing the insulating layer are performed.The second sacrificial pattern is formed between the first sacrificialpatterns. The second etch process is a dry etch process.

The method of forming a micro pattern in a semiconductor deviceaccording to the second embodiment of the present invention comprisesthe steps of forming an target layer, a hard mask layer and firstsacrificial patterns on a semiconductor substrate on which a cell gateregion, a selective transistor region and a periphery circuit region aredefined; forming an insulating layer and a second sacrificial layer onthe hard mask layer and the first sacrificial patterns; removing theinsulating layer and the second sacrificial layer formed in theselective transistor region and the periphery circuit region; performingthe first etch process so as to allow the second sacrificial layerformed in the cell gate region remain on the insulating layer betweenthe first sacrificial patterns for forming second sacrificial patterns;removing the insulating layer placed on the first sacrificial patternsand between the first and second sacrificial patterns in the cell gateregion; etch the hard mask layer through the second etch processutilizing the first and second sacrificial patterns as the etch mask toform a mask pattern; and etch the target layer through the third etchprocess utilizing the hard mask pattern as the etch mask.

The target layer is formed of a tungsten silicide (WSi_(x)) layer. Thestack structure consisting of a tunnel insulating layer, a firstconductive layer for a floating gate, a dielectric layer and a secondconductive layer for a control gate is formed between the target layerand the semiconductor substrate. The hard mask layer has a stackstructure consisting of an amorphous carbon layer and a siliconoxynitride (SiON) layer. The first sacrificial layer is formed of apolysilicon layer, a silicon oxide (SiO₂,) layer, a tungsten layer or aSOG (spin on glass) layer. The first sacrificial pattern has a criticaldimension that is approximately half of a pitch between the micropatterns formed through the final process.

The insulating layer is formed from amorphous carbon layer, siliconoxide (SiO₂), a tungsten (W) or a SOG (spin on glass). The insulatinglayer is formed from material having an etch selectivity with respect tomaterial utilized for forming the second sacrificial layer and the firstsacrificial pattern. The insulating layer deposited on a side surface ofthe first sacrificial pattern has a thickness that is approximately halfof a pitch between the micro patterns formed through the final process.

The second sacrificial layer is formed from conductive material orinsulative material. The second sacrificial layer is formed of a SOG(spin on glass) layer, an organic bottom anti-reflective coatingcontaining silicon such as a multi-functional hard mask layer, a siliconoxide (SiO₂) layer, a tungsten (W) layer or a polysilicon layer. A heattreatment process is further performed after forming the depositionprocess if SOG material is utilized. The second sacrificial layer isremoved through a dry etch process utilizing the insulating layer as anetch stop layer when a process for removing the second sacrificial layerformed in the selective transistor region and the peripheral region isperformed. The insulating layer is removed through a dry etch processutilizing the hard mask layer as an etch stop layer when a process forremoving the insulating layer formed in the selective transistor regionand the peripheral region is performed. The second sacrificial layerremained in the selective transistor region is removed when a processfor removing the second sacrificial layer remained in the cell gateregion is performed. The second sacrificial layer remained in theselective transistor region is removed through the etch-back process.

The second sacrificial pattern is leveled with the first sacrificialpattern when the first etch process is performed. The insulating layerhas an etch selectivity with respect to material utilized for formingthe first sacrificial pattern and the second sacrificial layer when thefirst etch process and the process for removing the insulating layer areperformed. The insulating layer remained in the selective transistorregion is removed when a process for removing the insulating layerremained in the cell gate region is performed. The insulating layerremained on the selective transistor region is removed through a dryetchetch process utilizing oxygen (O₂) plasma. The second sacrificialpattern is formed between the first sacrificial patterns. The secondetch process is a dry etch process. The tunnel insulating layer, thefirst conductive layer for the floating gate, the dielectric layer andthe second conductive layer for the control gate formed between thetarget layer and the semiconductor substrate are etched to form the gatewhen the third etch process is performed.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A to FIG. 1F are sectional views of a semiconductor device forillustrating a method of forming a micro pattern in a semiconductordevice according to the first embodiment of the present invention; and

FIG. 2A to FIG. 2H are sectional views of a semiconductor device forillustrating a method of forming a micro pattern in a semiconductordevice according to the second embodiment of the present invention.

DESCRIPTION OF SPECIFIC EMBODIMENTS

Hereinafter, the embodiments of the present invention will be explainedin more detail with reference to the accompanying drawings.

FIG. 1A to FIG. 1F are sectional views of a semiconductor device forillustrating a method of forming a micro pattern in a semiconductordevice according to the first embodiment of the present invention, FIG.1A to FIG. 1F show that the process of forming a micro pattern isperformed on only a cell gate region.

Referring to FIG. 1A, an etching-subject (or target) layer 101, a hardmask layer 102 and a first sacrificial layer 104 are sequentially formedon a semiconductor substrate 100. At this time, the hard mask layer 102has a stack structure consisting of an amorphous carbon layer 102 a anda silicon oxynitride (SiON) layer 102 b, and the first sacrificial layer104 is formed from material such as polysilicon, silicon oxide (SiO₂,),tungsten (W) or spin on glass. Here, the target layer 101 is formed of alayer such as an insulating layer, a conductive layer or aninter-insulating layer.

Subsequently, a bottom anti-reflective coating (BARC) 106 andphotoresist patterns 108 are formed on the first sacrificial layer 104.At this time, the photoresist patterns 108 are formed such that a pitchbetween the photoresist patterns is twice as large as that between themicro patterns to be obtained in the final process.

Referring to FIG. 1B, the bottom anti-reflective coating 106 and thefirst sacrificial layer 104 are etched by utilizing the photoresistpatterns 108 as an etch mask to form first sacrificial patterns 104 a.At this time, when an etch process is performed for etch the firstsacrificial layer 104, an upper portion of the silicon oxynitride layer102 b constituting the hard mask layer 102 may be etched. The aboveprocess is performed for preventing a generation of a bridge in asubsequent process. The bridges are formed by having portions of thefirst sacrificial layer 104 remaining on the hard mask layer 102.

The photoresist patterns 108 are then removed. At this time, the bottomanti-reflective coating 106 may be removed when the photoresist patterns108 are removed. The first sacrificial patterns 104 a are formed suchthat a critical dimension (CD) of the first sacrificial pattern 104 a isapproximately half of a pitch between the micro patterns formed throughthe final process.

Referring to FIG. 1C, an insulating layer 110 is formed on the hard masklayer 102 and the first sacrificial patterns 104 a. At this time, theinsulating layer 110 may be formed from a material such as amorphouscarbon, silicon oxide (SiO₂), a tungsten (W) or a SOG (spin on glass).Here, the amorphous carbon layer is formed as the insulating layer 110because the amorphous carbon layer has an etchetch selectivity which isthe same as that of a second sacrificial layer 112 (to be formed in asubsequent process) and of material utilized for forming the firstsacrificial pattern 104 a so that the amorphous carbon layer may beremoved without damaging the first sacrificial patterns 104 a during asubsequent process for removing the insulating layer 110. Accordingly,material having an etch selectivity with respect to the secondsacrificial layer 112 and material utilized for forming the firstsacrificial pattern 104 a may be utilized for forming the insulatinglayer 110. The insulating layer is formed such that a thickness of theinsulating layer 110 formed on a side surface of the first sacrificialpattern 104 a is approximately half of the pitch of the micro patternsto be formed through the final process.

Then, the second sacrificial layer 112 is formed on the insulating layer110 so as to fill a space between the first sacrificial patterns 104 a.At this time, the second sacrificial layer 112 is formed from conductivematerial or insulative material. The second sacrificial layer may beformed of a SOG (spin on glass) layer having an excellent gap-fillproperty, an organic bottom anti-reflective coating containing siliconlike a multi-functional hard mask layer, a silicon oxide (SiO₂) layer, atungsten (W) layer or a polysilicon layer. Since SOG material contains asignificant amount of impurities and moisture, if SOG material isutilized for forming the second sacrificial layer, a heat treatmentprocess may be performed for removing the impurities and moisture afterthe second subsidiary layer has been formed.

Referring to FIG. 1D, the second sacrificial layer 112 is etched untilan upper side of the insulating layer 110 is exposed. At this time, theetch process is performed using an etch-back process. When the processfor removing the second sacrificial layer 112 is performed, the topportion of the second sacrificial layer 112 that is surrounded by theinsulating layer 110 is leveled with the top portion of the firstsacrificial pattern 104 a.

Subsequently, the insulating layer 110 exposed by the process foretching the second sacrificial layer 112 and the insulating layer 110formed between the first sacrificial pattern 104 a and the secondsacrificial layer 112 are removed such that the insulating layer 110remains on only a lower side of the second sacrificial layer 112 to formsecond sacrificial patterns 112 a. The second sacrificial pattern andthe first sacrificial pattern are formed in alternating manner. At thistime, the insulating layer 110 is removed through a dry etch processutilizing oxygen plasma. The insulating layer 110 has an etchetchselectivity with respect to the second sacrificial layer 112 andmaterial utilized for forming the first sacrificial pattern 104 a whenthe process for etch the second sacrificial layer 112 and the processfor removing the insulating layer 110 are performed. It is possible toobtain the desired pitch between the patterns by forming the secondsacrificial pattern 112 a between the first sacrificial patterns 104 aas described above.

Referring to FIG. 1E, the hard mask layer 102 is etched by utilizing thefirst sacrificial pattern 104 a and the second sacrificial pattern 112 aas the etch mask to form the hard mask pattern 102 c having thepredetermined line and space. At this time, the hard mask layer 102 isetched through a dry etch process. The first sacrificial pattern 104 a,the insulating layer 110 and the second sacrificial pattern 112 a areremoved to form a micro pattern consisting of the hard mask pattern 102c.

Referring to FIG. 1F, the target layer 101 etched by utilizing the hardmask pattern 102 c having the predetermined line and space as the etchmask to form an etching-subject (or target) pattern 101 a. The hard maskpattern 102 c is removed.

As described above, the micro pattern is formed through only theprocesses of forming the first sacrificial pattern 104 a and the secondsacrificial pattern 112 a so that the micro pattern having the desiredcritical dimension (CD) may be formed. Also, in the method according tothe present invention, the conventional process for forming a spacer canbe omitted, and so a process time can be reduced.

A method according to the present invention can be applied to a methodof manufacturing a NAND flash memory device as follows.

FIG. 2A to FIG. 2H are sectional views of a semiconductor device forillustrating a method of forming a micro pattern in a semiconductordevice according to the second embodiment of the present invention.

Referring to FIG. 2A, an etch-subject (or target) layer 201 is formed ona semiconductor substrate 200 on which a cell gate region A, a selectivetransistor region B and a periphery circuit region C are defined. Atthis time, the target layer 201 is formed of a tungsten silicide(WSi_(x)) layer, and a stack structure consisting of a tunnel insulatinglayer, a first conductive layer for a floating gate, a dielectric layerand a second conductive layer for a control gate is formed between thetungsten silicide (WSi_(x)) layer and the semiconductor substrate 200. Ahard mask layer 202 and a first sacrificial layer 204 are sequentiallyformed on the target layer 210. At this time, the hard mask layer 202has a stack structure consisting of an amorphous carbon layer 202 a anda silicon oxynitride layer 202 b, and the first sacrificial layer 204 isformed from material such as polysilicon, silicon oxide (SiO₂,),tungsten (W) or SOG (spin on glass).

Subsequently, a bottom anti-reflective coating 206 and first photoresistpatterns 208 are formed on the first sacrificial layer 204. At thistime, the photoresist patterns 208 are formed such that a pitch betweenthe photoresist patterns is twice as large as that between gate lines tobe formed in the final process.

Referring to FIG. 2B, the bottom anti-reflective coating 206 and thefirst sacrificial layer 204 are etched by utilizing the firstphotoresist patterns 208 as an etch mask to form first sacrificialpatterns 204 a. At this time, when an etch process is formed for etchingthe first sacrificial layer 204, an upper portion of the siliconoxynitride layer 202 b constituting the hard mask layer 202 may beexcessively etched. The above process is performed for preventing ageneration of a bridge in a subsequent process caused by a portion ofthe first sacrificial layer 204 remaining on the hard mask layer 202.

The first photoresist patterns 208 are then removed. At this time, thebottom anti-reflective coating 206 may be removed when the firstphotoresist patterns 208 are removed. The first sacrificial patterns 204a are formed such that a critical dimension (CD) of the firstsacrificial pattern 204 a is approximately half of the pitch of themicro patterns formed through the final process.

Referring to FIG. 2C, an insulating layer 210 is formed on the hard masklayer 202 and the first sacrificial patterns 204 a. At this time, theinsulating layer 210 may be formed from material such as amorphouscarbon, silicon oxide (SiO₂), tungsten (W) layer or SOG (spin on glass).Here, the amorphous carbon layer is formed as the insulating layer 210because the amorphous carbon layer has an etch selectivity which is thesame as that of the material constituting a second sacrificial layer 212(to be formed in a subsequent process) and the first sacrificial pattern204 a so that the amorphous carbon layer may be removed without damagingthe first sacrificial patterns 204 a during the subsequent process forremoving the insulating layer 210. Accordingly, material having an etchselectivity with respect to the second sacrificial layer 212 andmaterial utilized for forming the first sacrificial pattern 204 a may beutilized for forming the insulating layer 210. The insulating layer isformed such that a thickness of the insulating layer 210 formed on aside surface of the first sacrificial pattern 204 a is approximatelyhalf of the pitch of the micro patterns to be formed through the finalprocess.

Then, the second sacrificial layer 212 is formed on the insulating layer110 so as to fill a space between the first sacrificial patterns 204 a.At this time, the second sacrificial layer 212 is formed from conductivematerial or insulative material. The second sacrificial layer may beformed of a SOG (spin on glass) layer having an excellent gap-fillproperty, an organic bottom anti-reflective coating containing siliconlike a multi-functional hard mask layer, a silicon oxide (SiO₂) layer, atungsten (W) layer or a polysilicon layer. Since SOG material containsplenty of impurities and moisture, if SOG material is utilized forforming the second sacrificial layer, a heat treatment process may beperformed for removing impurities and moisture after a depositionprocess.

Referring to FIG. 2D, photoresist patterns 214 are formed on the secondsacrificial layer 212 in the cell gate region A to open the selectivetransistor region B and the peripheral region C.

Referring to FIG. 2E, the second sacrificial layer 212 and theinsulating layer 210 formed in the selective transistor region B and theperipheral region C are etched by utilizing the second photoresistpatterns 214 as the etch mask. At this time, the second sacrificiallayer 212 is removed through a dry etch process utilizing the insulatinglayer 210 as an etch stop layer for preventing an upper portion of thesilicon oxynitride (SiON) layer 202 b constituting the hard mask layer201 from being damaged when the etch process is performed, and theinsulating layer 210 is then removed through a dry etch processutilizing the silicon oxynitride (SiON) layer 202 b as an etch stoplayer. The second photoresist patterns 214 are removed.

Referring to FIG. 2F, the second sacrificial layer 212 formed in thecell gate region A is etched through an etch process until an upper sideof the insulating layer 210 is exposed. At this time, the etch processis performed using an etch-back process. When the process for etchingthe second sacrificial layer 212 formed in the cell gate region A isperformed, the top portion of the second sacrificial layer 212 thatsurround by the insulating layer 210 is leveled with the firstsacrificial pattern 204 a, and when the process for etching the secondsacrificial layer 212 formed in the cell gate region A is performed, thesecond sacrificial layer 212 formed in the selective transistor region Bis also removed until a portion of the insulating layer 210 is exposed.

Subsequently, the insulating layer 210 exposed through the process foretching the second sacrificial layer 212 in the cell gate region A andthe insulating layer 210 formed between the first sacrificial pattern204 a and the second sacrificial layer 212 are removed such that theinsulating layer 210 remains on only a lower side of the secondsacrificial layer 212 to form second sacrificial patterns 212 a in thecell gate region A. At this time, the insulating layer 210 is removedthrough a dry etch process utilizing oxygen plasma. Here, the insulatinglayer 210 has an etch selectivity with respect to the second sacrificiallayer 212 and material utilized for forming the first sacrificialpattern 204 a when the process for etching the second sacrificial layer212 and the process for removing the insulating layer 210 are performed.When the process for removing the insulating layer 210 formed in thecell gate region A is performed, the insulating layer 210 remaining inthe selective transistor region B is also removed. It is possible toobtain the desired pitch between the patterns by forming the secondsacrificial pattern 212 a between the first sacrificial patterns 204 aas described above.

Referring to FIG. 2G, the hard mask layer 202 is etched by utilizing thefirst sacrificial pattern 204 a and the second sacrificial pattern 212 aas the etch mask to form the hard mask pattern 202 c having thepredetermined line and space. At this time, the hard mask layer 202 isremoved through a dry etch process. The first sacrificial pattern 204 a,the insulating layer 210 and the second sacrificial pattern 212 a aremoved to form a micro pattern consisting of the hard mask pattern 202 c.

Referring to FIG. 2H, the target layer 201 is etched by utilizing thehard mask pattern 202 c having the predetermined line and space as theetch mask to form an -target pattern 201 a. At this time, when thetarget layer 201 is etched, the tunnel insulating layer formed betweenthe target layer 201 and the semiconductor substrate 200, the firstconductive layer for the floating gate, the dielectric layer and thesecond conductive layer for the control gate are simultaneously etchedto form the gate. The hard mask pattern 202 c is removed.

As described above, the micro pattern is formed through only theprocesses of forming the first sacrificial pattern 204 a and the secondsacrificial pattern 212 a so that the micro pattern having the desiredcritical dimension (CD) may be formed. Also, in the method according tothe present invention, the conventional process for forming a spacer canbe omitted, and so a process time can be reduced. In addition, when theprocess for etching the second sacrificial layer 212 and the insulatinglayer 210 formed in the selective transistor region B and the peripherycircuit region C is performed, it is possible to inhibit the firstsacrificial pattern 204 a and an upper portion of the silicon oxynitridelayer 202 b constituting the hard mask layer 202 from being damagedbecause the insulating layer 210 having the etch selectivity withrespect to the second sacrificial layer 212 and material constitutingthe first sacrificial pattern 204 a is formed below the secondsacrificial layer 212.

Although embodiments have been described with reference to a number ofillustrative embodiments thereof, it should be understood that numerousother modifications and embodiments can be devised by those skilled inthe art that will fall within the spirit and scope of the principles ofthis disclosure. More particularly, variations and modifications arepossible in the component parts and/or arrangements of the subjectcombination arrangement within the scope of the disclosure, the drawingsand the appended claims. In addition to variations and modifications inthe component parts and/or arrangements, alternative uses will also beapparent to those skilled in the art.

The present invention as described above has the following advantages:

First, the micro pattern is formed through only the processes of formingthe first sacrificial pattern and the second sacrificial pattern, and sothe micro pattern having the desired critical dimension (CD) may beformed.

Second, since the conventional process for forming a spacer can beomitted, a process time can be reduced.

Third, when the process for etching the second sacrificial layer and theinsulating layer formed in the selective transistor region and theperiphery circuit region is performed, it is possible to inhibit thefirst sacrificial pattern and an upper portion of the silicon oxynitridelayer constituting the hard mask layer from being damaged because theinsulating layer having the etch selectivity with respect to the secondsacrificial layer and material constituting the first sacrificialpattern is formed below the second sacrificial layer.

1. A method of forming a fine pattern in a semiconductor device, themethod comprising: forming a target layer, a hard mask layer and firstsacrificial patterns over a semiconductor substrate; forming aninsulating layer and a second sacrificial layer over the hard mask layerand the first sacrificial patterns; performing a first etch process soas to allow the second sacrificial layer to remain over the insulatinglayer between the first sacrificial patterns for forming secondsacrificial patterns; removing the insulating layer provided over thefirst sacrificial patterns and between the first and second sacrificialpatterns; etching the hard mask layer through a second etch processutilizing the first and second sacrificial patterns as an etch mask toform a hard mask pattern; and etching the target layer through a thirdetch process utilizing the hard mask pattern as an etch mask.
 2. Themethod of claim 1, wherein the target layer is formed of an insulatinglayer, a conductive layer or an inter-insulating layer.
 3. The method ofclaim 1, wherein the hard mask layer has a stack structure including anamorphous carbon layer and a silicon oxynitride (SiON) layer.
 4. Themethod of claim 1, wherein each first sacrificial pattern is formed of apolysilicon layer, a silicon oxide (SiO₂,) layer, a tungsten layer or aSOG (spin on glass) layer.
 5. The method of claim 1, wherein each firstsacrificial pattern has a critical dimension that is approximately halfof a pitch between the fine patterns formed through the final process.6. The method of claim 1, wherein the insulating layer is formed fromamorphous carbon layer, silicon oxide (SiO₂), a tungsten (W) or a SOG(spin on glass).
 7. The method of claim 1, wherein the insulating layeris formed from material having an etch selectivity with respect tomaterial utilized for forming the second sacrificial layer and the firstsacrificial patterns.
 8. The method of claim 1, wherein the insulatinglayer deposited on a side surface of each first sacrificial pattern hasa thickness that is approximately half of a pitch between the finepatterns formed through the final process.
 9. The method of claim 1,wherein the second sacrificial layer is formed from conductive materialor insulative material.
 10. The method of claim 1, wherein the secondsacrificial layer is formed of a SOG (spin on glass) layer, an organicbottom anti-reflective coating containing silicon such as amulti-functional hard mask layer, a silicon oxide (SiO₂) layer, atungsten (W) layer or a polysilicon layer.
 11. The method of claim 10,further comprising performing a heat treatment process after forming thedeposition process if SOG material is utilized.
 12. The method of claim1, wherein the second sacrificial layer is etched through the etchbackprocess.
 13. The method of claim 1, wherein the second sacrificialpatterns are leveled with the first sacrificial patterns when the firstetch process is performed.
 14. The method of claim 1, wherein theinsulating layer is removed through a dry etch process utilizing oxygen(O₂) plasma.
 15. The method of claim 1, wherein the insulating layer hasan etch selectivity with respect to material utilized for forming thefirst sacrificial patterns and the second sacrificial layer when thefirst etch process and the process for removing the insulating layer areperformed.
 16. The method of claim 1, wherein each second sacrificialpattern is formed between adjacent first sacrificial patterns.
 17. Themethod of claim 1, wherein the second etch process is a dry etchprocess.